Vacuum-pump.



PATENTED JUNE 16, 1908.

J. ZEITLIN. VACUUM PUMP. rrmornon Hmm un. s, laos.

2 suini-9.8mm L PATENTED JUNE 16, 1908.

J. ZEITLIN.. VACUUM PUMP. APPLIoA'rIoN FILED APR. 1905.

2 SHEETS-SHEET 2 mm a;

JOSEPH ZEITLIN, OF KENSINGTON, ENGLAND.

vacUUM-PUMP.

Specification of Letters Patent.

Patented June 16, 1908.

Application led April 8, 1905.v Serial No. 254,463.-

To all whom 'it may concern: e

Be it known that l, JOSEPH ZEITLIN, a citizen of Russia, but at presentresiding at 5 Gilston road, Kensington, in the county of London,England, student, have invented a certain new and useful ImprovedVacuum- Pump, of which the following is a specification.

This invention relates to a vacuum pum in which by the oscillation ofthe Jump cyll inder, the cylinder is connected a ternately with an inletand a discharge passage. The piston is connected with the driving crankthrough an elastic piston rod which enables the piston to be closedagainst the end of the cylinder without damage thereto and to be heldthere while the communication between the cylinder and one passage isbeing closed and that between the cylinder and the other passage isbeing established. By thus. eliminating all valves, in the ordinarysense, and all clearance between the piston and cylinder end at the endof each discharge and the beginning of each suction stroke, a very highvacuum can be speedily attained.

The invention is illustrated in the accompanying drawings in whichFigures l and 2 are central longitudinal sections taken at right an lesto each other of the pump cylinder and distributing valve g Fig. 3 1s aview similar to Fig. l, but with the pump iston and cylinder in anotherposition g ig. 4 is an end elevation partly in section, showing thepreferred manner of supporting the distributing valve plug; Fig. 5 is aplan view of the said valve plug Fig. 6 is a sectional elevation showinga pair of distributinv valve plugs cou led for series working and Fig. 7is a detai showing the intercommunication cock in position for parallelworking.

The pump cylinder a is closed at one end only bya cover b attached to orcombined with which is a hollow casing or sleeve c the ends of which arejournaled in fixed bearing blocks d. The interior of the casing isconeshaped throughout part of its length -as shown at c', in which partis fitted a corresponding coned plug e which is stationary in workingbut which is provided with means for adjustment whereby a gas tightjoint may be maintained between the coned plug and its envelopingsleeve. The plug e has near the middle of its conical part two partialtransverse passa es f g in a common transverse plane, whic extend fromthe peri hery of the plug into the interior thereof, an communicate attheir inner ends respectively with two longitudinal passages g/ leadingto the respective ends 'of the p ug e. Suitable provision is made forcoupling the ends of the plu e with pipes as shown in Fig. 6.

The cylinder cover b remains fully open and is provided with a singleport b which is arranged to place the interior of the cylinder intoalternate communication with the passages f and g, sleeve c are rockedabout the axis of the latter. By this means during the suction stroke ofthe piston the pump cylinder is placed in`communicati0n only with thevessel to be exhausted, and during the delivery stroke only with theatmosphere or with the vessel into which the exhaust gases are to bedelivered.

The piston h is reciprocated by any suitable drlving mechanism, as by arevolving crank i which is connected with a crosshead k sliding inguides k i'ixed to or formed with the open cover Z of the pum cylinder.The piston is connected with t e crosshead in such manner that there isa certain lost motion between the two at each change of direction ofmovement of the crosshead, and a spring m inter osed between thecrosshead and piston ten s to keep the piston rod at its maxlmumelongation. i

The throw oi. the crank is arranged to be greater than is required toreturn the piston 71v against the cylinder cover b, so that when theplston reaches this position it is held there during a part of therevolution of the crank, during which the spring lm is compressedbetween the crosshead and piston as shown in Figs. 1 and 2, and the pumpcylinder is rocked through the angle required to cut off communicationthrough the port b between the interior of the cylinder and the deliverypassage g g. The continued movement of the cylinder establishescommunication with the suction inlet passage f j as shown in Fig. 3, andthe spring is again extended` lt will be obvious that instead of anoscillating cylinder and a stationary distributing when the cylinder andthev tain guickly a high valve, the cylinder may be stationary and thedistributing valve operated by any sultable .means from a movin part ofthe apparatus so as to place thecy inderin communil cation with thesuction and delivery passages alternately at the required interyals. Itwill also be obvious that by reversing the rotation of the drivingcrank, the f unctions of the passages ff and g w1ll be mterchanged.`

The plston h as usually one or more leather packing rings r preferablcup-shaped which are clamped between dis s s with the natural insidesurface of the leather against the cylinder wall, and pressed outwards'against the cylinder by means of spring packing rings t of the usualdescription which are inclosed within the cup leather. The internalspring packing rings form ayielding abutment surface for Lthe softleather packing while pressing it into close contact with the cylinderwall, this construction forming an effective nas tight joint, which alsomay be lubricated by a dry lubricant instead of oil.

As shown in Figs. 2, 5 and 6, the plug e is preferably forme with oneend e s uared and mounted with a small amount o freedom in one lateraldirection in a block n which is also squared externally and is in turnmounted in another block o with a small amount of lateral freedom in thetransverse direction. The block o is mounted and centered in the bearingblock d in which it is secured by means of set screws p. Thisarrangementrenders the plug e practically selfcentering and self-adjusting when itis tightened in the sleeve c by means of the nut g on its other end. f

Two or more pumps such as described may be used simultaneously toexhaust a vessel and may be arranged either in parallel with each otheras a single pump having a ca acity equal to the sum of the capacities othe separate pumps, or in series with each other, one exhausting fromthe vessel and delivering to the next of the series, and so on, the lastof the series delivering to the atmosphere. A check valve may beinterposed in the final delivery passage to prevent ingress of airthereto at the beginning of the discharge stroke.

It 1s sometimes convenient, in order lto obvacuum such as is require inelectric incandescence lamps, to effect the preliminary exhaustion bymeans of two or more pumps arranged in parallel, andthe final exhaustionby these pumps arranged in series, and the change from the onearrangement to the other may be quickl effected by connecting thesuction and eliveryy passages of the pumps with each other throng 1suitable intercommunication cocks. Such a device for two pumps A, B isshown in Fig. 6 of the drawings, in which the suction and deliverypassages of pump A, and the suction assage of t e pump B are connectedto thes ell C of an intercommum'cation cock having a three-way plug tapD. With the tap shown in the position of ig. 6, the pump delivers intothe pump B which in turn delivers to the atmosphere, the pumps beingconnected in series. position shown in Fig. 7, the suction passa es ofboth pumpsare in communication with each other, whiletheir deliverypassages communicate with the atmosphere, the pumps bein then cinarallel.

Having t us descrl ed the nature of my said invention and the best meansI know of carrying the same into practical eiect, I claim:- y

1. A vacuum pump comprising acylinder, a cylinder cover, a single portin said cover and adapted to be always fully o en, a piston connectedelastically with tie driving motor, such elastic connection permittingthe piston to be safely driven against the cylinder end and held thereduring the last portion of the exhaust stroke and commencement of thesuction stroke, a distributing valve plug having in a common transverseplane suction inlet and exhaust openings, and means whereby saidcylinder is disconnected from the exhaust opening and connected with theinlet opening while the piston is stationary against the cylinder end;substantially as described.

2. In combination with `two or more reversible vacuum pumps such asherein described, means for connecting such pumps in series or inparallel with each other, substantially as described.

3. In a vacuum pump having an oscillat- With the plug in the in cylindersuch as herein described, a dis' trl uting valve comprising a hollowvalve casing integral with the cylinder head and journaled in fixedbearings su porting the weight of the pump, a conical p ug having in acommon transverse plane suction inlet and exhaust openings, one end ofsaid plug mounted with limited lateral freedom in one direction in ablock mounted in a second block havin lateral freedom in a transversedirection, W ereby said plug can be adjusted centrally with respect tothe axis of the valve casing; substantially as described.

4. A reversible vacuum pump comprising an oscillating cylinder, acylinder cover, a single port in said cover and adapted to be alwaysfully open, a cross head, a piston, an elastlc connection between theplston and drivin motor operating during the last portion o the exhauststroke and commencement of the suction stroke, and a distributing valveplug havin in a common transverse plane suction in et and exhaustopeningsa ternately putgingcommunication with the cylinder by theoscillation thereof, with In testimony whereof I have signed my meansfor disconnecting the cylinder from name to this specification in thepresence of the exhaust opening Whlle the piston is sta- W o subscribingWitnesses. l

tionary against the cylinder end and means l lJOSEPH ZEITLIN. foroscillating the cylinder and for recipro- Witnesses: eating said crosshead; substantially as dei JOSEPH WILLARD, scribed WALTER J. SKERTEN,

